Police have spoken out after blocked roads in the capital saw ambulance officers delayed in responding to a heart attack at the Parliament protest yesterday. 

Superintendent Scott Fraser said today will maintain a significant presence at Parliament as they work to find solutions for the disruption the protest is causing. 

These disruptions have been widespread, and in some cases dangerous. On Friday night, a protester suffered a medical event, and because of the hundreds of vehicles blocking the roads surrounding Parliament, ambulances could not get to him. 

"This caused a delay in his treatment with ambulance staff having to walk some distance to get to the man who was waiting with Police," Fraser said. 

"Despite the very difficult environment, our staff, and our Wellington Free Ambulance colleagues, acted with empathy and professionalism, ensuring this man got the medical treatment he needed." 

Police plan to work with tow trucks to try and remove more than 100 vehicles still blocking Molesworth St, but tow truck drivers have been threatened by protesters 

In response to safety concerns, Metlink is stopping all buses from travelling the Lambton Interchange "with immediate effect" and putting detours in place. 

"We have taken this decision with everyone's health and wellbeing at the forefront of our plans and we thank passengers for their patience during this time." 

Front lawn of Parliament a 'mud pit' 

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. 

A Herald reporter says the damage to the front lawn is significant, describing it as a "mud pit".