From Thursday, the tax authority will send a direct website link by text to some people who want to find their reference number or reset a password.

It is expecting 170,000 calls this month with simple questions before the self-assessment tax return deadline.

MPs have slammed HMRC for a poor call handling record over the years.

More than 12 million people are required to complete tax self-assessments online before 31 January, but some are left frustrated by long waits on HMRC's phonelines when trying to get help.

The trial will continue until the start of April, and is designed to free up the call handlers for more complex issues.

A text answer will be triggered based on a customer's reason for calling. Routine requests that will be answered with a text and a website link include:

* Locating a Unique Tracking Taxpayer Reference (UTR) number

* Registering for HMRC online services

* Resetting a lost or forgotten online service password or user ID

Callers will also be given the option to receive an online link or speak to someone to deal with other inquiries such as help filling in their tax return, getting a National Insurance by letter, or requests for income and employment history.

Similar technology has been widely adopted by other businesses and services, and is far from cutting-edge, but HMRC is battling against a poor customer service reputation.

Earlier this month, the Public Accounts Committee of MPs said that taxpayers and their accountants were receiving an unacceptable level of service from HMRC.

The number of tax authority customer service staff has been cut from 25,500 to 19,500 in the last five years.

"We were surprised to learn that at times in the past, HMRC has simply closed its telephone line when it could not cope with demand. It is not acceptable not to answer calls from people who are trying to pay the government money," the committee said.

It said that HMRC's plan was to move people onto better-received online services, but it questioned whether this would reduce demand for phonelines, improve the quality of service, or be appropriate for all circumstances or customers.

Richard West, director of personal tax operations at HMRC, said: "Redirecting these sorts of queries to online services should help customers find the answer more quickly. It also means calls from customers during the current self-assessment peak, whose questions cannot easily be answered online and require help from an adviser, get the appropriate support they need.

"Customers who cannot use digital services will be able to get support in the normal way. This is available through our telephony service and through our extra support team for those who have difficulty using our other services."