Auckland Transport is considering building a two-lane busway between Panmure and Botany via Pakuranga.

The new council-controlled agency has prepared artists' impressions of two versions of such a project, for presentation to a public open day in the Pakuranga town centre tomorrow.

They entail departures from an earlier plan, which was for single bus lanes on each side of Pakuranga Rd and Ti Rakau Drive as part of a $1.33 billion package of road and public transport upgrades called the Auckland Manukau Eastern Transport Initiative (Ameti).

The new proposal is either for a two-lane busway pointing in both directions in the centre of each road, or on one side only, leaving two general traffic lanes heading each way.

An Auckland Transport spokesman said yesterday that planners had no particular preference between the alternatives, and were keen to hear what the community might have to say tomorrow.

He was unable to provide a timetable or cost for the busway before more detailed investigations next year, although he said the agency hoped to keep within the original Ameti budget.

Whichever version is chosen, the busway will be developed in stages, starting with the section between Panmure and Pakuranga and then along Ti Rakau Drive towards Botany.

The object is to develop a bus rapid transit system from Botany to the Panmure railway station, where passengers will be able to switch transport modes under a new integrated public transport ticket to be introduced from late next year.

Auckland Transport major projects manager Rick Walden said his agency did not believe single kerbside bus lanes would allow effective rapid transit as buses would need to slow down for turning traffic.

There would also be safety problems for residents getting in and out of driveways.

A central busway would allow two lanes of general traffic to flow unimpeded alongside it on each side.

Bus stops would be stationed at controlled intersections, to allow passengers to cross the road safely.

General traffic would be allowed to make u-turns at the intersections.

The transport organisation is less explicit about the workings of a two-lane busway on one side of the road.

Cars will not be allowed to cross the busway to reach roadside properties, meaning slip lanes may have to be built for access to homes and businesses from intersections.

Mr Walden said that although Pakuranga had the second-lowest level of public transport use in the region - after Whangaparaoa - Auckland Transport believed there was enough potential demand for a rapid transit corridor between Panmure and Pakuranga.

"The problem is that buses are delayed by the same congestion as other vehicles," he said.

"Encouraging more people into public transport is an important part of dealing with the congestion that is holding back economic growth in the area."

Auckland Council Howick ward member Jami-Lee Ross, said the busway could not come quickly enough as congestion on Ti Rakau Drive could add up to 30 minutes to trips between Flatbush and Pakuranga.

He was also looking forward to construction of a flyover of Ti Rakau Drive between Reeves Rd and the Southeastern Highway, a source of serious congestion. Transport Auckland expects to start building it in 2019.

The flyover is aimed at providing a direct line for traffic from Bucklands Beach and Howick to the Southeastern Highway, bypassing the Pakuranga town centre and leaving the Panmure Bridge largely free for buses.

Even so, Auckland Transport is considering widening the bridge to create room for the busway.

But Panmure Community Action Group spokesman Keith Sharp said last night that planners were having difficulties working out how to replace the Panmure roundabout with controlled intersections, and the busway would only add to the challenge.

Ameti community open day - 10am-4pm tomorrow at Te Tuhi Arts Centre, 13 Reeves Rd, Pakuranga. Auckland Transport will hold a presentation from 11am.