It's a soggy start to the fifth day of the anti-mandate protest which is occupying Parliament's front lawn.

Protesters clad in raincoats and carrying umbrellas are pressed up against the barricades put up in front of Parliament, occasionally yelling at journalists on the media balcony to "tell the truth".

They are periodically breaking into song, with the national anthem being heard over the calls of megaphones.

More vehicles have arrived and joined the hundreds that have been blocking the streets near Parliament since Monday, with members of the Freedom and Rights Coalition expected to rejoin the occupation later this morning.

As rain continues to fall in the capital, the lawns of Parliament are looking more like a battleground - complete with trenches.

Speaker of the House Trevor Mallard turned the sprinklers on last night and left them running in an effort to make the protesters uncomfortable, hoping it would make them leave.

"They're not legally on the ground, so there is no problem adding a little to their discomfort."

In response, protesters placed cones over the sprinklers and dug irrigation trenches to re-direct the water.