Half-hour parking vouchers have been introduced to ease difficulties with the new pay-by-phone parking method.

From this week, Barnet Council has introduced the £1 half-hour vouchers, which are available for purchase online through its website.

A one-hour voucher costs £2. One-hour and half-hour vouchers are also available to buy in the borough's 16 libraries, with a minimum order of four.

Since one-hour parking vouchers were introduced in December, 3,628 have been sold online.

The number of motorists now registered to pay for parking by phone in Barnet has risen to 162,437, an increase of 30,000 since pay and display machines were decommissioned in December.

The change has caused uproar among shoppers and traders, who claim the scheme is "killing the high streets".

Parking was among the hottest topics at a Talk London event in Hendon last week, hosted by London Mayor Boris Johnson.

Campaigners attended in matching t-shirts emblazened with slogans opposing pay-by-phone payment methods.

Barnet Traders' Association chairman Gail Laser conceded at the meeting that she believed the payment method was "here to stay", despite her involvement in campaigns to fight it.

She said: "The way it was introduced was very poor and I think the council needs to look at several issues.

"Our high streets are dying on their feet and I do think the council are starting to see that. It has been the death knell for our high streets."

Leader of the Council, Councillor Richard Cornelius, said: "While the majority of Barnet motorists are now realising the benefits of cashless parking, we have listened to businesses and introduced the one-hour and now half-hour sessions pre-paid scratch cards."

Traders across the borough have vowed to band together to oppose the council's parking scheme following a forum on the issue in North Finchley in December.