UPDATE 1-Subaru was lax on final inspection rules for Japan cars -sources

* Subaru revelation follows govt-ordered internal investigation

* Subaru shares fall more than 3 pct

* About 300,000 Subaru vehicles could be affected - Nikkei

* Subaru inspection practice went on for over 30 years - Kyodo (Adds company comment, background on scandal, changes slug)

TOKYO, Oct 27 (Reuters) - Subaru Corp failed to follow proper inspection procedures for vehicles destined for the domestic market at a factory in Japan, two people with knowledge of the matter said on Friday.

The revelation follows a similar issue at Nissan Motor Co and comes as Japanese manufacturers grapple with wider compliance problems with Kobe Steel Ltd saying on Thursday it had found more possible cases of data fabrication on its products.

Shares of Subaru fell more than 3 percent in early trade, underperforming a slight rise in the broader Tokyo market .

Japan's transport ministry had instructed domestic automakers to conduct internal investigations after Nissan found violations on inspections governing vehicles sold in Japan at its domestic factories. The ministry had set an end-October deadline for submitting the results.

The sources told Reuters that Subaru had allowed uncertified technicians to conduct final vehicle inspections at its main Gunma factory complex, north of Tokyo, which violates ministry requirements. They asked not to be identified because they were not authorised to disclose the information.

The Nikkei business daily reported earlier that Subaru had yet to determine whether a recall, which could affect 300,000 vehicles, would be necessary.

A Subaru spokesman said the company could not comment on the inspection issue because the automaker had not submitted results of its internal investigation to the transport ministry yet.

Kyodo News reported separately that Subaru had been letting uncertified technicians oversee final inspections for over 30 years, without citing its source. (Reporting by Maki Shiraki; Writing by Chang-Ran Kim and Sam Holmes)