A slew of rainbow coloured streamers have appeared across Melbourne’s east overnight in support of same-sex marriage.

Images obtained by 9NEWS showed the colourful ribbons tied around trees, power poles and street signs from Ferntree Gully to Boronia this morning.

Genevieve Baldry, who snapped the photographs, told 9news.com.au she was heading to the shops when she made the discovery.

The colourful streamers lined the streets in the city's east. (Supplied)

Local woman Genevieve Baldry found the streamers during a walk this morning. (Supplied)

It is not yet known who is behind the cheerful campaign. (Supplied)

There are reports of similar streamers popping up on streets more than 60 kilometres away. (Supplied)

“I was delighted to see hundreds and hundreds of rainbow streamers all around town,” Ms Baldry said.

She said it was a great way to celebrate LGBTQI Pride, and hoped it would inspire the community to vote “yes” on the postal plebiscite on same-sex marriage in September.

It is not yet known who was behind the wave of rainbow sweeping the city, but Ms Baldry said she had heard there were also streamers in Chirnside and Point Cook.

The Australian Electoral Commission said last week there had been a surge in "electoral transactions" ahead of the vote, recording 68,000 on one day alone when a daily average would average 4000.

Former Liberal leader John Hewson described it as the "Theresa May effect", named for the British prime minister who was expected to win the recent UK election by a landslide, but ended up with a minority government because of an unusual amount of young people voting and backing Labour.

"The young vote in this country is so readily discounted," Dr Hewson told Sky News today.

"It is potentially, I think, so significant and now will be mobilised."