Prime Minister Anthony Albanese says the first anniversary of the October 7 attacks on Israel carries “terrible pain”, and the impact of that day has “reverberated around the globe”.

Police are on alert as vigils and ceremonies are held across Australia on Monday, marking one year since Hamas militants massacred 1200 people in Israel and captured hostages.

Pro-Palestine rallies are also scheduled on Monday after thousands of protesters gathered in Sydney and Melbourne on Sunday in defiance of authorities condemning the timing of the marches.

The protests were peaceful and there was only a handful of arrests after police vowed to crack down on any violent or antisemitic behaviour.

With tensions high across the nation, Albanese released a video message calling for social cohesion.

He said since the October 7 atrocities, Jewish Australians had felt the “cold shadows of antisemitism reaching into the present day”.

“As a nation we say never again,” Albanese said.

“We unequivocally condemn all prejudice and hatred – there is no place in Australia for discrimination against people of any faith.”

Albanese said the deadly Hamas attacks were a “terrorist atrocity” that had caused distress in Australia.

He also said the loss of lives in the Middle East conflict was a “devastating tragedy”.

“As we mourn and reflect, we also reaffirm a fundamental principle of our shared humanity: every innocent life matters,” he said.

“Today, we reflect on the truth of our shared humanity, of the hope that peace is possible, and the belief that it belongs to all people.”

Members of the Jewish community joined Israeli Ambassador Amir Maimon at a commemoration in Sydney on Sunday night.

Maimon said October 7 was the beginning of a “painful chapter” for Israel.

“We did not ask for this war,” he told those gathered at Sunday’s vigil overlooking Sydney Harbour.

“We did not start it.

“We did not want it, but we are determined to win it.”

There will also be pro-Palestinian rallies on Monday. Up to 2000 people are expected at a resilience rally at Lakemba Mosque in Sydney’s south, which has not been authorised by NSW police.

Thousands rally for Palestine

It follows Pro-Palestine rallies across Australia on Sunday, the eve of the anniversary, as supporters vow to continue marching.

Large crowds gathered at Sydney’s Hyde Park shortly after noon on Sunday before heading towards St James Road, while similar scenes unfolded in Melbourne.

Sydney rally organiser, Amal Naser said the CBD march was the beginning of action to mark one year since the October 7 attacks and Israel’s subsequent violence in Gaza.

“It is not us who supports terror, it is our government,” Naser told the crowd.

“Every time we thought it couldn’t get worse, Israel showed us it could get worse – 12 months in, there is no sign Israel will slow down.

“We stand here in, I think one of the biggest rallies we have ever seen.”

One man was arrested in Sydney after holding up an Israeli flag with a Nazi swastika in the position of its Star of David.

Demonstrators had been warned not to display the flag, symbols or portraits of Hezbollah, which is a designated terrorist group in Australia, or “play out” the conflict in the Middle East through racial slurs or “threats to public safety”.

Some marchers carried flags with green and yellow, the colours of Hezbollah’s official ensign.

One man holding a green and yellow flag – which appeared to show a masked man holding a weapon, echoing the design of the Hezbollah flag – was quizzed by police.

NSW Police Assistant Commissioner Peter McKenna said there were about 10,000 people there.

“I did say before the operation that we wouldn’t tolerate criminal offending and anti-social behaviour and I think that message got through,” he said.

In Melbourne, police said four people were arrested for public order-related matters as more than 7000 marched in support of Palestine.

One group of men dressed in black was seen waving green and yellow flags as thousands gathered outside the State Library in the CBD.

Last weekend, protesters in Sydney and Melbourne drew condemnation for waving the flag of Hezbollah at a similar march.

One protester said some in the group had family links to Hezbollah, as it has seats in Lebanon’s parliament.

He said the colours symbolised resistance and they would have waved the flags even if the use of Hezbollah flags had not been criticised during the week.

Men in the group were also seen waving a flag with an image of Iran’s current and former leaders.

Australian Palestine Advocacy Network president Nasser Mashni told the Melbourne crowd Israel should be condemned for its offensive in Gaza in the wake of October 7.

“Will anyone speak of the dead children, dead women and dead men?” Mashni said.

“It’s shameful that we’re being asked to be respectful when we’ve had 365 October 7s in this period.”

The crowd then marched down Swanston Street towards Flinders Street Station, chanting phrases including “all Zionists are terrorists”. Some waved solid yellow or green flags.

Victoria Police had a visible presence and quickly led a man away when a scuffle broke out.

Deputy Prime Minister Richard Marles said the protests were “deeply regrettable”.

“The anniversary of October 7 needs to be about October 7 and what happened on that day,” he told ABC’s Insiders program.

Victorian Premier Jacinta Allan said it was “deeply inappropriate” that protests were being held the day before the anniversary.

Similar rallies in Perth and Adelaide drew hundreds in support of Gaza.

More than 1200 people were killed during the October 7 attack and 250 people were taken hostage by Hamas, according to the Israeli government.

In response, Israel unleashed a bombing campaign and ground invasion of Gaza, killing almost 42,000 people, displacing 1.9 million and leaving another 500,000 with catastrophic levels of food insecurity, local health ministry sources report.

-with AAP