Shareholders of Envirosuite, a microcap which has seen its stock price more than double since last month, are being offered shares at almost four times the price of an unusual share issue to the personal trust of a Chinese national just four weeks ago.

The $125 million ASX-listed company, which supplies software systems that track environmental pollutants in real-time, on Thursday requested its shares be placed in a trading halt in relation to a "proposed capital raise" but did not give further details.