The massive hunt for two teenagers suspected of shooting dead Australian tourist Lucas Fowler and his US girlfriend Chynna Deese has moved to the eastern Canadian province of Ontario with police receiving more than 30 tips within an eight-hour period.

Key points: If the fugitive teens are in Ontario, they have travelled more than 5,000km

If the fugitive teens are in Ontario, they have travelled more than 5,000km Police have warned of unreliable information being shared on social media

Police have warned of unreliable information being shared on social media There are still no confirmed sightings of the pair since they were seen in Gillam, Manitoba

The Ontario Provincial Police (OPP) announced on Friday it has set up an investigative team headed by a senior detective to follow up on potential sightings of Bryer Schmegelsky, 18, and Kam McLeod, 19.

"The OPP is following up on every tip it receives," OPP Sergeant Carolle Dionne said.

"Yesterday alone we received over 30 tips in less than eight hours.

"We ask anyone who believes they have observed these two suspects to report it to police immediately."

Lucas Fowler was farewelled by family and friends in Sydney on Friday. ( AP )

But police have also asked the public not to spread rumours on social media, warning of "misinformation".

If the fugitives are in Ontario they have eluded authorities while travelling more than 5,000 kilometres. That's 1,000km further than the distance between Sydney and Perth.

One unconfirmed sighting of the duo in recent days was of "a suspicious" white vehicle driving through a construction zone on a highway in the small community of Kapuskasing, Ontario.

OPP Criminal Investigation Branch Detective Inspector Matt Watson will lead the new investigative team.

Police in Greater Sudbury, in southern Ontario, asked the public to report sightings through official channels.

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"Any confirmed sightings will be shared through GSPS social media sites," Sudbury Police wrote on Twitter on Friday.

"We urge the community to rely on the GSPS social media/website as their trusted source of info. Should any sighting be confirmed we will issue a community notification immediately."

The alleged crime spree began on July 14 in the western province of British Columbia (BC) when the bodies of Mr Fowler, 23, from Sydney, and his North Carolina girlfriend Chynna Deese, 24, were found shot dead on the side of a highway.

Four days later, on another BC highway, the teenagers allegedly murdered botanist Leonard Dyck and then drove 3,000km east across Canada's north to the tiny town of Gillam, Manitoba.

On July 23 their stolen Toyota RAV4 was dumped outside of Gillam and set on fire.

There have been no confirmed sightings of the duo since.

Kapuskasing is 2,360km south-east of Gillam.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 11 seconds 1 m 11 s Canadian police say specialised teams are being pulled out of the search for Kam McLeod and Bryer Schmegelsky

Royal Canadian Mounted Police and the Royal Canadian Air Force, using teams on the ground and planes in the air with infrared cameras and imaging radar, unsuccessfully searched 11,000 square kilometres around the town of Gillam and surrounding wilderness before scaling back the hunt.

The RCMP and OPP have urged members of the public to call them immediately to report a possible sighting instead of posting information on social media.

If the suspects are spotted, authorities urged the public to take note of every detail.

Police insist the search is "not over", despite the decision to scale down operations in Manitoba. ( Reuters/RCMP Manitoba )

"Sharing as much information as possible on your observation is important such as type of vehicle, vehicle plate, description of clothing, direction of travel," Sergeant Dionne said.

"But most importantly, do not approach them as they are considered to be dangerous."

Mr Fowler's father, Chief Inspector Stephen Fowler, told a Sydney memorial service on Friday that his son was living "a life that many of us envied" and he will "live on in our hearts".

Hundreds of the 23-year-old's family and friends gathered at the Uniting Church in Turramurra to honour his life.

A memorial service was held for Lucas Fowler in Sydney. ( ABC News: Mark Reddie )

AAP/ABC